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Ms Margaret Lagorio Project 880-040 IA November 11, 2002 Page 3 GROUNDWATER MONITORING RESULTS On October 10, 2002, groundwater samples and depth to water data were collected from ' monitoring wells MW-1 through MW-5 The groundwater monitoring event was coordinated with the Blaine Tech Environmental who monitors the adjacent 76 Station east of the subject site Groundwater samples were analyzed for the presence of Total Petroleum Hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, xylenes (BTEX), and for five gasoline oxygenates (MtBE, di-isopropyl ether [DIPE], ethyl tert- butyl ether [ETBE], tert-amyl methyl ether [TAME], and tert-butyl alcohol [TBA]) using U S Environmental Protection Agency (EPA) Methods 8015, 602, and 8260B (Modified) Field and laboratory procedures are presented as Attachment A Certified analytical reports, chain-of-custody documentation, and field data sheets are presented as Attachment B Fourth Quarter Groundwater Monitoring Results Depth to groundwater at the site decreased approximately 0 84 feet since the previous sampling event conducted on July 23, 2002 During the fourth quarter groundwater flow was generally to the northeast at an average gradient of 0 001 ft/ft, which is consistent with previous sampling events Groundwater elevation data are presented in Table 1 A groundwater elevation contour map based on the October 7, 2002 data is shown on IFigure 1 TPHg were reported in wells MW-1 and MW-3 at concentrations of 6,300 and 250 micrograms per liter (gg/l), respectively Unidentified compounds in the TPHg range were reported in well MW-2 at concentrations of 99 gg/l Benzene was reported in well MW-1 at a concentration of 500 ggA MtBE was reported in all wells sampled at concentrations ranging from 220 µg11 in well MW-3, and 29,000 gg/l in well MW-5 TAME was reported in wells MW-1, MW-2, and 1 W-4 at concentrations ranging from 43 µg/1 in well MW-2, and 110 µg/1 in well MW-4 TBA was reported in wells MW-1, MW-4 and MW-5 at concentrations of 3,900, 140, and 5,600 pg/l, respectively SAC W\SacDP120021PRJ1PJ8188018800401A 2aD doc 021d 1 (01070000)